1. Technical Field
The present invention relates to ventilating apparatuses, and more particularly to a ventilating apparatus applied to a wire bonder for semiconductor devices in order to ensure circulation of protective gas.
2. Description of Related Art
In the known packaging technology for semiconductor devices, wire bonding is used to achieve transmission of signals on dies to carriers (e.g. leadframes, substrates, etc.), and external terminals (e.g. solder balls or lead fingers of lead frames, etc.) then serve for connection to PCBs. Formation of such a wire bond mainly involves using a capillary to deliver a metal wire, such as a copper wire, a silver wire, a gold wire or the like, and forming a FAB (Free Air Ball) at the distal of the wire while implementing a gas supplying device to continuously provide protective gas so as to secure good formation of the FAB. The foregoing protective gas is preferably nitrogen gas, argon gas or nitrogen and hydrogen mixed gas. Therein, nitrogen gas and argon gas are capable of protecting the FAB from oxidization, and hydrogen in nitrogen and hydrogen mixed gas can further restore the oxidized part of the FAB, thereby facilitating good formation of the FAB. At last, the FAB connected with the wire bond is attached to the die or a pad on the carrier. Thus, effective control of the wire bonding process can be achieved, and in turn the high yield of semiconductor packaging can be ensured. As to the wire bonding process, some prior arts such as U.S. Pat. No. 6,234,376 and U.S. Pat. No. 4,575,602 have proposed the approach of employing a ventilating apparatus to deliver protective gas to the melted copper wire or gold wire so as to facilitate sintering the spherical FAB. However, both of the prior arts are limited to unidirectional provision of protective gas and disadvantageously lead to unstable or turbulent flow of protective gas in the ventilating apparatus, which in turn causes abnormal FAB sintering, such as brakeage, eccentrics, damage, chipping and so on, each leading to failed die after the wire bonding process.
On the other hand, there are prior arts focused on maintaining protective gas around the formed FAB until the wire bonding process so as to protect the FAB from oxidization and in turn from abnormalities. Therein, an additional gas pipe is required to supply the protective gas such as nitrogen gas, argon gas or nitrogen and hydrogen mixed gas to the formed FAB. However, the additional gas pipe needs to be mechanically controlled and this certainly means increased costs for equipment and inconvenience in operation.